Found whilst helping my bride's friend clear out her late parents' garage...
I have that tool too. Its for the inner door and window clips on Mopar car in the fifties. It maybe for other uses. I have a old Proto catalogue and it was in there.
Gee and I thought it was for making Steers from Bulls.
No thanks, Dennis.
What Neil said - also Packard's going by e-bay ads. They seem to sell pretty good there and one was priced $125.00